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The :mod:`deformer` module provides techniques to generate modulated paths. All
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classes in the :mod:`deformer` module can be used as attributes when
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drawing/stroking paths onto a canvas, but also independently for manipulating
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previously created paths. The difference to the classes in the :mod:`deco`
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module is that here, a totally new path is constructed.
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drawing/stroking paths onto a canvas. Alternatively new paths can be created by
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deforming an existing path by means of the :meth:`deform` method.
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All classes of the :mod:`deformer` module provide the following methods:
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*curvesperhloop*: the number of Bezier curves to approximate a half-loop
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*sign*: with ``sign>=0`` starts the cycloid to the left of the path, ``sign<0``
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*sign*: for ``sign>=0`` the cycloid starts to the left of the path, whereas
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for ``sign<0`` it starts to the right.
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*turnangle*: the angle of perspective on the 3D spring. At ``turnangle=0`` one
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sees a sinusoidal curve, at ``turnangle=90`` one essentially sees a circle.
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*turnangle*: the angle of perspective on the 3D spring. At ``turnangle=0``
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results in a sinusoidal curve, whereas for ``turnangle=90`` one essentially
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.. class:: smoothed(radius, softness=1, obeycurv=0, relskipthres=0.01)
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This deformer creates a smoothed variant of the original path. The smoothing is
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done on the basis of the corners of the original path, not on a global skope!
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done on the basis of the corners of the original path, not on a global scope!
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Therefore, the result might not be what one would draw by hand. At each corner
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(or wherever two path elements meet) a piece of length :math:`2\times` *radius*
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(or wherever two path elements meet) a piece of twice the *radius*
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is taken out of the original path and replaced by a curve. This curve is
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determined by the tangent directions and the curvatures at its endpoints. Both
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are given from the original path, and therefore, the new curve fits into the gap
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are taken from the original path, and therefore, the new curve fits into the gap
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in a *geometrically smooth* way. Path elements that are shorter than
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*radius* :math:`\times` *relskipthres* are ignored.
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points with infinte curvature. The resulting path stops at such points and
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leaves the too strongly curved piece out.
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* When the original path contains self-intersection, then the resulting parallel
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path is not continuous in the parameterisation of the original path. It may
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first take a piece that corresponds to "later" parameter values and then
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continue with an "earlier" one. Please don't get confused.
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* When the original path contains on or more self-intersections, then the
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resulting parallel path is not continuous in the parameterisation of the
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original path. This may result in the surprising behaviour that a piece
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that corresponding to a "later" parameter value is followed by an
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The parameters are the following:
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*distance* is the minimal (signed) distance between the original and the
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*relerr* is the allowed error in the distance is given by ``distance*relerr``.
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*relerr* is the allowed relative error in the distance.
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*sharpoutercorners* connects the parallel pathitems by wegde build of straight
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lines, instead of taking circular arcs. This preserves the angle of the original
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*sharpoutercorners* connects the parallel pathitems by a wegde made of
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straight lines, instead of taking circular arcs. This preserves the angle of
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the original corners.
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*dointersection* is a boolean for performing the last step, the intersection
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step, in the path construction. Setting this to 0 gives the full parallel path,
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which can be favourable for self-intersecting paths.
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*checkdistanceparams* is a list of parameter values in the interval (0,1) where
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the distance is checked on each parallel pathitem
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the distance is checked on each parallel pathitem.
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*lookforcurvatures* is the number of points per normpathitem where its curvature
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is checked for critical values
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is checked for critical values.
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manual/deformer.rst
